INDUSTRY NEWS

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New Acronyms... 

FHS - The Future Homes Standard sets the performance expectations for new homes — things like fabric efficiency, airtightness, heating system type, carbon targets and overall energy performance. 

HEM - The  Home Energy Model (HEM) is simply the calculation engine used to prove that a new home meets those FHS requirements. It will eventually (Summer 2027?) replace SAP!

In other words:

• FHS = the rules that will replace Part L
• HEM = the method used to show you’ve met the rules

HEM replaces SAP because FHS needs a more modern, dynamic model that can accurately represent heat pumps, PV, battery storage, hourly energy demand and low‑carbon system behaviour.

Until HEM is ready, a new updated SAP 10.3 will be the primary methodology 

 From 24 March 2027, new homes must follow this new Part L (HEM) — which includes:

• 75% CO₂ reduction vs 2013 baseline
• Mandatory low‑carbon heating
• Mandatory on‑site renewable electricity generation (typically solar PV) 
• Higher fabric standards
• Compliance via HEM or SAP 10.3 during transition

ON SITE RENEWABLE ENERGY GENERATION

Requirement = 40% of heated ground‑floor area of the dwelling. This is panel area, not roof area.

Example: If the ground‑floor area is 50m², the required PV panel area is: 0.4 × 50 = 20 m²   That’s typically 4–5 kWp, depending on panel efficiency.  

This should be considered now for future planning applications to ensure you meet the requirement

TRANSITIONAL ARRANGEMENT

As previous regulatory changes there will be a transition period.

To remain on Part L 2021 instead of moving to the Future Homes Standard 

• A building control application (initial notice, building notice, or full plans) is submitted before 24 March 2027. 
• Construction genuinely commences on that specific plot before 24 March 2028 — meaning the sub‑structure is completed, not just site clearance or material ordering.

Goodbye gas and oil boilers!